Vegetable aerating proteins

ABSTRACT

OIL-FREE VEGETABLE PROTIEN, PREFERABLY SOYA, IS HYDROLYZED IN THE PRESENCE OF ACID OR ALKALI TO GIVE HYDROLYZED PROTIEN HAVING A APREDETERMINED DEGRADATION AS DETERMINED BY VISCOSITY MEASUREMENTS OF AQUEOUS SOLUTIONS, THE HYDROLYZED PROTIEN THEN FURTHER MODIFIED WITH PEPSIN TO YIELD PEPSIN MODIFIED HYDROLYZED PROTIEN WHICH IN THE PRESENCE OF WATER AND SURGAR, WHIPS AT A RAPID RATE OF PRODUCE AERATED PRODUCTS OF LOW DENSITY.

United States Patent C 3,814,816 VEGETABLE AERATING PROTEINS Robert C.Gunther, Galesburg, Ill., assignor to A. E. Staley ManufacturingCompany, Decatur, Ill.

No Drawing. Continuation of abandoned application Ser. No. 700,383, Jan.25, 1968. This application Feb. 8, 1971, Ser. No. 113,756

Int. Cl. A23j 3/02; A231 1/20 U.S. Cl. 426-46 16 Claims ABSTRACT OF THEDISCLOSURE This is a continuation of application Ser. No. 700,383 filedJ an. 25, 1968, now abandoned.

In the food industry, proteinaceous materials, such as egg whites,hydrolyzed milk proteins and soy albumen, have been used for many yearsas aerating agents. By an aerating agent is meant a material capable ofentrapping air in an aqueous mix, such as the basic sugar-syrup mix usedin the confectionery trade or the flour-sugar mixes used in the bakeryfield. A basic requirement of a good aerating material is, that itpossess the ability to entrap the maximum quantity of air in the minimumlength of time. In other words, such a product should whip rapidly to ahigh volume. The economies realized are rather obvious when such aproduct is used since the desired degree of aeration can be achievedwith a minimum amount of whipping agent.

Egg albumen, hydrolyzed milk proteins and soy albumen, althougheffective in whipping air into certain type mixes, are lacking in totalwhipping efiicacy and consequently must be utilized at relatively highconcentrations to produce the desired degree of aeration.

This is also true of products of the types described in U.S. Pats.2,381,407 and 2,502,029. The products described in U.S. Pat. 2,381,407which are made by using papain as an enzyme modifying agent have pooraerating power and provided whipped products of a relatively highdensity. The products of U.S. Pat. 2,502,029 are comparable to ordinarysoy albumen. In these products the starting protein is extracted but nothydrolyzed. The resultant products leave much to be desired from thestandpoint of aerating ability and flavor.

One of the objects of this invention is to provide a new and improvedprotein material which can be whipped to produce an aerated product.

Another object is to produce an aerating substance of greatly improvedwhipping characteristics, greater water solubility, and a more blandflavor.

A further object of the invention is to provide a new and improvedprocess for producing vegetable aerating protein which in the presenceof water and sugar whips at a rapid rate to give aerated products of lowdensity. Other objects will appear hereinafter.

In accomplishing these objects in accordance with this invention anoil-free vegetable protein, preferably soya protein, and preferably aprotein that has been extracted in an alkaline aqueous solution, ishydrolyzed either in alkaline or acidic aqueous media to give ahydrolyzed protein having a predetermined degradation as determined byviscosity measurements of its aqueous solutions, and

then further modified with pepsin to produce a pepsin 70 modifiedhydrolyzed protein which, in the presence of 3,814,816 Patented June 4,1974 water and sugar, will whip at a rapid rate to produce aeratedproducts of low density.

For optimum results the hydrolyzed protein should be insoluble in waterat its isoelectric point but should be sufficiently hydrolyzed that theviscosity of a 10% by weight solution of said hydrolyzed protein inwater at pH 9.5 to 48 C. is not more than 100 centipoises, preferably5-20 centipoises.

This invention is predicted upon the discovery that vegetable proteinswhich have been so hydrolyzed will produce upon pepsin enzymehydrolysis, a completely dif ferent type product than would be obtainedby the enzyme hydrolysis of the unmodified protein source. By acompletely different type product is meant a product which has at leasttwice the whipping efficiency of theconventional product, and also aproduct with much improved flavor.

In accordance with one embodiment of this invention, a proteinaceousmaterial such as oil-free soybean meal or flakes may be extracted withan aqueous alkaline solution (e.g., sodium carbonate, sodium hydroxide),preferably at a pH in the range of 7.5-10.0 and a temperature of 30-50C. The insolubles may be removed from the extract solution either byfiltration or centrifugation and the clarified extract liquor is given arelatively mild alkaline hydrolysis by treatment with an alkali (e.g.,sodium hydroxide or calcium hydroxide) at a temperature of 50 85 C. for1 to 2 hours (the amount of alkali used will ordinarily be from 5% to10% by weight of the protein content of the extract liquor). The amountof alkali used, the temperature and length of time of the treatment willbe determined by the degree of hydrolysis desired. It is most importantthat the hydrolysis be terminated before the protein is hydrolyzed tothe point that it would be soluble at its usual insoluble isoelectricpH. Following hydrolysis, the pH is adjusted to the isoelectric pH ofthe protein, pH 4.1-4.5, and the precipitated curd is washed free ofsoluble carbohydrates, minerals, etc., by decantation.

The enzymatic modification is carried out by first treat ing thepurified alkaline modified protein curd with a suitable acidifying agentsuch as sulfuric or hydrochloric acid to produce a pH ordinarily in therange of 1.2 to 2.5 and at a temperature of 25 C. to 40 C. The enzyme,pepsin (1:10,000 strength), is then added in an amount usually of 0.05to 0.5% by weight of the protein content of the solution.

Enzyme modification is allowed to proceed for 18 to 24 hours, afterwhich the solution may be heated to C. to stop enzyme action. The pH isthen adjusted to 5.0 to 5.5 with caustic, and the solubles separatedfrom the insolubles by filtration or centrifugation. The clear aqueoussolution containing the solubles is then spray dried to produce a verylight colored, free flowing product.

Two products made in accordance with this invention, (referred to forconvenience as E-500) were compared for whipping efficiency with soyalbumen, a hydrolyzed milk protein and egg albumen in both an ice-boxchifion mix and a conventional corn syrup sugar mix. The comparativetest results are set forth in Table A.

TABLE A /20 corn syrup/sugar Chocolate chifion pie 1 Percent whippingagents used based on total dry weights.

The applications and uses of a whipping agent with the whippingefficiency and relatively bland flavor of the E-500 type proteindesignated above are many and varied. One of the outstanding propertiesof the E-500 type whipping proteins is its ability to aerate whole eggmixes. Egg albumen, soy albumen and hydrolyzed milk protein will notproduce this effect. For example, 260 grams fresh whole eggs and 5 gramsE-SOO type protein can be Whipped to a specific gravity of 0.19 in 2minutes in a Mixmaster beater. This is a stiff, rigid whip which can hefolded into batters, etc.

This same amount of fresh whole eggs with as much as to grams of eggalbumen (or soy albumen or hydrolyzed milk protein) showed no aerationeven after 10 to 15 minutes whipping.

Consequently, one of the principal specific applications of this newprotein product is in a prepared sponge cake mix in which whole eggs areadded to the dry, prepared mix and whipped to a light aerated batter.

Also, an E-500 type protein, because of its low flavor level andwhipping efiiciency, finds usage in other prepared (or packaged) cakemix products. In packaged angel food cake mixes, this whipping proteingreatly improves the egg white foam whipping rate and volume.

The E-500 proteins can also be used in dry chiffon pie mixes, which bythe simple addition of hot water, can be whipped in a matter of minutesto a light, flutfy chiffon. This whipped chiffon is then placed in a pieshell and chilled to set the filling. In this case, the conventionalwhipping agents will require 3 to 4 times longer whipping time toproduce the same degree of aeration.

In general, it may be stated that the very high whipping efficiency andthe low flavor level of the E500 type proteins make them particularlyadaptable to dry, packaged food mixes in which rapid aeration isdesired. The chiffon mixes, angel food cake mixes, icing mixes, etc.,represent but a few of the many applications of this protein in thattype of product.

In the general method of preparation outlined above, the alkalinehydrolysis was carried out on the extraction liquor after separationfrom insolubles but prior to iso lation of the glycinin from sugars,salts, etc. This is but one of several methods of this invention. Thealkaline hydrolysis can be made directly on the soybean meal or flakes,or it can be made on the purified isolated glycinin curd after washingout all Water soluble materials.

As the alkali to be used in the hydrolysis of the protein, it ispreferred to employ an alkali metal or alkaline earth metal hydroxide,caustic soda alone or in conjunction with lime being particularlyeffective. The temperature of the hydrolysis may vary considerablydepending upon the particular set of conditions being used, butordinarily the protein modification (hydrolysis) would be conducted inthe range of 40 C. to 80 C. The enzyme modification of the partiallyhydrolyzed protein is carried out in the pH range of 1.2 to 2.5 and attemperatures in the range of C. to 50 C. The concentration of 1:10,000strength pepsin is generally in the range of 0.05% to 0.7% of the amountof protein being used. Larger amounts of pepsin can be utilized but foreconomical reasons, this is not considered practical.

Following enzyme modification, the pH of the reaction slurry is usuallyadjusted to between 3.0 and 5.5 prior to separation of the solubles fromthe insolubles. Also, the slurry may be heated to anywhere between 40 C.and 100 C. to precipitate heat coaguable protein and to facilitate thefiltration operation, although this is not a necessary procedure,depending upon the type of product desired. The heating can be carriedout either before or after adjusting the pH.

In the practice of this invention, the various conditions of thealkaline hydrolysis such as temperature, time, concentration of alkali,pH, etc., may be varied to a considerable extent without materiallyaffecting the characteristics of the end product provided that severalfactors are varied simultaneously. Thus, it is obvious that in general adecrease in temperature may be compensated by an increase in thestrength of the alkali employed or by an increase n the duration of thehydrolysis.

The invention will be further illustrated, but is not limited, by thefollowing examples in which the quantities are stated in parts by weightunless otherwise indicated.

EXAMPLE I One hundred pounds of oil-free soybean flakes was slurried in1000 pounds of water at a temperature of 30 C. for 10 minutes. One and ahalf (1 /2) pounds of caustic soda in 4 pounds water was added and theslurry mixed continuously for 1 hour. The insoluble flake residue wasseparated from the soluble matter by centrifugation. After separation ofthe solubles from the insolubles, the extract liquor was heated to C.and 1 pound of 35% hydrogen peroxide was added rapidly to thecontinuously stirred solution. After 10 minutes, 4 pounds of 50% causticsoda was added and the solution held with gentle agitation at 80 C. for30 minutes. The solution was then adjusted to pH 4.4 with 10% sulfuricacid to precipitate the partially modified glycinin curd. Theprecipitated curd was separated and Washed twice by decantation with1200 pounds Water at room temperature.

The washed curd (at a temperature of 30 C.) then was treated with 20%hydrochloric acid to give a pH of 1.3. At this stage the curd wasapproximately dissolved. Pepsin 1:10,000 in the amount of 57 gramsdissolved in 500 ml. water was added and the mixture stirred for 4hours. After 2 hours and 4 hours, the pH of the solution was adjustedback to 1.3 with 20% hydrochloric acid. The total enzyme modificationtime was 20 hours. After modification, the solution was heated to 70 C.and the pH adjusted to 5.0 with 15% caustic soda solution. Ten pounds ofdiatomaceous filter aid was added and the solubles separated from theinsolubles by filtration. The filtered liquor was then spray dried toproduce a very light color, bland product. This product may bedesignated E-500 and is that indicated in Table A and described above.

EXAMPLE II One hundred pounds of oil-free soybean meal was slurried in2000 pounds of Water at 50 C. and mixed for 5 minutes-or untilcompletely wetted out. Caustic soda solution (15%) was added to give apH of 8.5, and the pH was maintained at 8.0 to 8.5 for 1 hour withcontinuous agitation. After separation of the solubles from theinsolubles by centrifugation, the pH of the extract liquor (at 50 C.)Was adjusted to 4.4 to 4.6 with 5% sulfuric acid at 50 C., and theprecipitated glycinin allowed to settle. The supernatant was decantedand the glycinin curd washed once more by decantation with 2000 poundsof water at 50 C. One and a half pounds of caustic soda in 4 poundswater and one and a half pounds of lime (calcium hydroxide) in 4 poundswater were added and the solution slowly agitated for 2 /2 hours. The pHof the solution was then adjusted to 4.4-4.6 with 15% sulfuric acid andthe precipitated curd was separated by decantation.

The enzyme modification of the partially hydrolyzed curd was carried outas described in Example I.

EXAMPLE In One hundred pounds of oil-free soybean flakes was slurried in2500 pounds of water at 50 C. and mixed for 15 minutes. A solution of 2pounds of caustic soda in 5 pounds of 50 C. water and a solution of 2pounds of lime in 5 pounds of 50 C. water were added and the slurryslowly agitated for 2 /2 hours at 50 C. The pH of the solution was thenadjusted to 4.4-4.5 with 10% hydrochloric acid. The precipitated curd,along with the flake residue, was separated by decantation and washedtwice with 2500 pounds of water at 30 C.

Then 20% hydrochloric acid was added to the washed curd and flakeresidue to give a pH of 1.5 at a temperature of 28 C. To the acid mixwas then added 100 g. of pepsin (1:10,000) in 400 ml. Water. The slurrywas continuously stirred for hours then let stand for 17 additionalhours, or a total enzyme treatment time of 22 hours. (After 1, 3 and 5hours, the pH was adjusted back EXAMPLE IV One hundred and fifty poundsof oil-free soybean flakes was slurried in 2000 pounds of water at atemperature of 35 C. for 5 minutes. Two and a half (2 /2) pounds ofcaustic soda dissolved in 5 pounds water was added and the slurrystirred continuously for 1% hours. After separation of the solubles fromthe insolubles by centrifugation, the extraction liquor was heated to 70C., and 8 pounds of 50% caustic soda solution was added and the solutionheld at 70 C. for 45 minutes. The pH of the solution was then adjustedto 4.5 with 10% hydrochloric acid and the precipitated glycinin curd wasseparated and washed twice by decantation with 2000 pounds of water at30 C.

The washed curd at 30 C. was then treated with 25% hydrochloric acid togive a pH of 1.6 twenty-seven grams of pepsin (1:10,000 strength)dissolved in 200 g. water was added and the mix slowly agitated for 3hours, after which time the pH was readjusted to 1.6 with hydrochloricacid. The mixture was allowed to stand 18 hours. Causitc soda was addedto bring the pH to 4.3, pounds of diatomaceous filter aid was added tothe mix and the solubles separated from the insolubles by filtration.Caustic soda solution was added to the clear filtrate to give a pH of5.1, Following concentration by evaporation to approximately 30% solids,the product liquor was spray dried.

The degree of alkaline hydrolysis of a partially degraded protein hasbeen determined by measuring the viscosity of a 10% solution of theprotein at 48 C. with a Brookfield viscometer. Some results of thesemeasurements are summarily reported below in Table B.

TABLE B 10% solution of protein (sodium hydroxide to Viscosity, pH 9.5)Source epsJ (1)- Isolated soya protein (not degraded). Commercial... 6,200 (2) e. do. 3, 000 (3) Experilrgntal protein (partially de- Example1.... 11

gm e (4) do. Example II..- 7

I Brookfield viscometer; temperature 48 C. 1 Viscosity measurements weremade on protein after alkali modification and before enzymemodification.

Percent Protein (N 6.25) 81.0 Moisture 4.0 Ash 14.0 Carbohydrate (diff)1.0

6 EXAMPLE v Acid hydrolysis of protein One hundred pounds of oil-freesoybean flakes was slurried in 1,000 pounds of water at 30 C. for 10minutes. A 15% caustic soda solution was added to the agitated slurry togive a pH 8.7, and the slurry stirred continuously for 1 hour. Theinsoluble flake residue was separated from the soluble matter bycentrifugation, and the insoluble residue washed once with 500 pounds ofwater at 30 C. The combined solutions were then adjusted to pH 4.3 with10% sulfuric acid to precipitate the glycinin curd. The curd wasseparated and washed twice by decantation with 1,200 pounds water at 30C.

The washed glycinin curd (containing approximately 12% solids by weight)was slurried in 200 pounds water and while stirring vigorously 30 poundsof concentrated (98%) sulfuric acid was added to produce an acidconcentration of 10%. This acid solution was then heated to C. and heldat 80 C. with slow agitation for 1 hour.

After 1 hour, the solution was diluted with 3000 pounds cold water andthe pH adjusted to 4.4 with 20% caustic solution to precipitate thepartially modified glycinin curd. The precipitated curd was separatedand washed twice by decantation with 3000 pounds of water at roomtemperature.

The washed curd was then enzyme modified with pepsin and processedfollowing the general procedure outlined in Example I, to produce a verylight colored, relatively bland protein product.

A 10% solution of the acid hydrolyzed protein from which the pepsinmodified product was prepared had a viscosity of 7.5 cps. (pH 9.5/48(3.).

The final product in the standard Chocolate Chiffon Whip Test readilywhipped to a minimum density of 0.310 g./ml. and required 2 minutes and30 seconds to achieve a density of 0.44 g./ml.

EXAMPLE VI To pounds of water at 30 C. in a 30 gallon tank was added 10pounds of solvent extracted soybean flakes. Caustic soda (15% solution)was added to obtain a pH of 8.5. The flakes slurry was then agitated for1 hour during which time the pH was maintained at 8.5 by the addition ofcaustic soda solution. Agitation was stopped and the slurry allowed tosettle for 2 hours. The clear supernatant liquid (comprisingapproximately /2 the original volume of the slurry) was removed andfiltered through a 60 mesh screen to separate small amounts of veryfinely dispersed flake material.

To the remaining slurry in the tank was added an equal volume of waterat 30 C. and the slurry agitated for 30 minutes at a pH of 8.5. Againthe suspension was allowed to settle for 2 hours and the clearsupernatant removed as before.

The two clear supernatant solutions were combined and then heated to 80C. for the alkaline hydrolysis. Caustic soda (40% solution) was added toobtain a pH of 11.8 and the solution gently agitated for 25 minutes.Hydrochloric acid (20%) was then added to obtain a pH of 4.4. Theprecipitated protein was allowed to settle for 4 hours and the clearsupernatant removed by decantation. The protein curd was washed oncewith cold tap water in an amount equal to the original volume of thesolution.

A sample of the washed curd was removed and further concentrated to 20%solids. After dissolving at pH 9.5 and heating to 48 C. for 1 hour, aviscosity determination was made. The viscosity was centipoises.

The solids of the washed curd in the tank were adjusted to 6%-7% by theaddition of water, and 20% hydrochloric acid added to obtain a pH of1.5. The slurry was then heated to 30 C. and 0.4% of 1:10,000 pepsin(based on weight of dry solids) added. The mix was stirred for r 7 hours(pH adjusted twice during this period to 1.5) and then allowed to standat 30 C. for 17 hours, or a total enzyme modification time of 22 hours.

At the end of this peroid, the solution was heated to 70 C., and causticsoda solution added to raise the pH of the solution to 5.1. Filter aidwas added and the soluble separated from the insolubles by filtration.

The clear liquor from the filter press was spray dried in a stream ofheated air to yield a light colored, freeflowing powder.

Using the chocolate chiffon whip test the minimum density of the Whippedproduct was determined to be 0.305 gram/ml. The time required to obtaina density of 0.44 g./ml. was one minute and forty-five seconds. A pepsinmodified soy protein made by a similar process without hydrolyzing theprotein, when tested in the same manner, had a minimum density of 0.409g./ml. and a whip rate of three minutes and fifty seconds to achieve adensity of 0.44 g./ml.

The chocolate chiffon whip test previously referred to in the examplesis carried out as follows: dry blend 154 g. of chocolate chiffon base (amixture of sucrose, nonfat milk powder, cocoa, starch and gelatin) and9.0 g. of whipping agent in the small bowl of a Mixmaster beater. Add240 ml. (1 cup) of boiling water and beat on highest speed (No. 12) for4 minutes. The density of the aerated mix is determined by weighing asample in a calibrated beaker.

Another way of evaluating the invention is with low moisture corn syrup.Thus, 4 pounds of corn syrup is placed in a beater. To this is added 0.1pound whipping agent mixed with 0.4 pound water. The resultant mixtureis whipped slowly until well mixed, then at high speed until maximumvolume is achieved. A cooked syrup is prepared by cooking a mixture of 2pounds of corn syrup, 4 pounds sucrose and 0.5 pound of water to 240 F.The hot syrup is added while mixing in a beater at low speed to the coldcorn syrup containing the whipping agent and the resultant mixture isbeaten at high speed for two minutes. The amount of aerated product ismeasured in ounces per gallon. It requires approximately 1% of whippingagent (1 pound to 100 pounds of syrup comprising 60% corn syrup and 40%sucrose) to give 60-64 ounces per gallon of whipped product. Theproducts of US. 2,502,029 require at least 2% or twice as much whippingagent to obtain the same amount of whip. Six or eight times as much ofthe products of US. 2,381,407 are required to obtain the same amount ofwhip.

In addition to advantages already mentioned, the process of theinvention gives high yields. The products have a bland flavor and arebetter tasting than products prepared without the hydrolysis step. Theproducts of the invention are completely soluble in water at theisoelectric point of the hydrolyzed protein. They are also soluble overthe entire pH range.

While the invention is particularly valuable where the protein used issoy protein, it can also be applied to other vegetable proteins, forexample, those derived from cottonseed, peanut, sesame and the like.

Where an acid is used to hydrolyze the protein, any nontoxic hydrolyzingacid can be used (e.g., sulfuric, hydrochloric and phosphoric). Mineralacids are preferred.

In the examples, where hydrogen peroxide is used, it is employedprimarily to improve color and can be omitted.

The purification of the protein initially by alkaline extractionfollowed by precipitation and washing are optional steps. Theprecipitation and separation of the protein from the mother liquor afterextraction are optional. However, if one does not precipitate theprotein at its isoelectric pH and remove the accompanying clearsupernatant liquor, a considerable amount of salts would be includedwith the protein to be enzyme modified and this gives a final whippingagent containing a higher sodium chloride content than is desirable.Similarly, after enzyme modification a purification step is optional butdesirable.

I claim:

1. A process ofpreparing aerating proteins which comprises the steps of:

-(a) hydrolyzing oil-free vegetable proteins under alkaline or acidconditions to give hydrolyzed proteins having a predetermineddegradation as determined by viscosity measurements of its aqueoussolutions, said hydrolyzed proteins being insoluble in water at itsisoelectric point but sufficiently hydrolyzed that the viscosity of a10% by weightsolution in water at pH 9.5 and 48 C. is at least 5centipoises and not more than 100 centipoises, and

(b) then further modifying the resultant hydrolyzed proteins with pepsinto produce pepsin modified proteins characterized as being soluble inwater at the isoelectric point of the hydrolyzed proteins of step (a)above and thereby obtain pepsin modified proteins which in the presenceof water and sugar whip at a rapid rate to produce aerated products oflow density.

2. A process as claimed in claim 1 in which said vegetable protein issoya and wherein after modifying of the protein with pepsin, the pepsinmodified protein in the form of aqueous slurry is adjusted to a pHbetween 3.0 and 5.5 to provide a water soluble soya protein portion anda water insoluble soya protein portion, the water soluble portion isseparated from the water insoluble portion and the water soluble portionis recovered to provide a pepsin modified protein which in the presenceof water and sugar whip at a rapid rate to produce aerated products oflow density.

3. A process as claimed in claim 1 in which said vegetable protein isextracted with an alkaline aqueous solution, any insoluble residue isseparated, the pH of the residual solution is adjusted to theisoelectric point, the resultant precipitate is separated, thenre-slurried in water before hydrolyzing.

4. A process as claimed in claim 1 in which the vegetable protein ishydrolyzed under alkaline conditions.

5. A process as claimed in claim 1 in which the vegetable protein ishydrolyzed under acidic conditions.

6. A process as claimed in claim 1 in which said hydrolyzed protein isinsoluble in water at its isoelectric point but is sufiicientlyhydrolyzed that the viscosity of a 10% by weight solution in water at pH9.5 and 48 C. is within the range of 5 to 20 centipoises.

7. A process as claimed in claim 1 in which the pepsin modifiedhydrolyzed protein in the form of an aqueous slurry is acidified to a pHof 3.0 to 5.5, heated to a temperature of between 40 C. and 100 C., thenfiltered and the solids recovered from the fi trate.

8. A process of preparing aerating soya protein which comprisesextracting oil-free soya bean meal or flakes with an aqueous alkalinesolution at a pH in the range of 7.5 to 10.0 and a temperature of 30 C.to 50 C., separating the insolubles from the extract solution,subjecting the extract liquor to alkaline hydrolysis at a temperature of50 C. to C., the hydrolysis being carried out until the hydrolyzedprotein is insoluble in water at its isoelectric point but sufficientlyhydrolyzed that the viscosity of a 10% by weight solution in water at pH9.5 and 48 C. is at least 5 centipoises and not more than centipoises,adding an acid to the hydrolyzate in suflicient amount to adjust the pHto the isoelectric pH of the protein, thereby causing precipitation ofthe protein, separating the precipitated protein, washing saidprecipitated protein with water to remove soluble carbohydrates andminerals and produce a purified alkalinemodified soya protein,acidifying said alkaline modified soya protein with an aqueous solutionof a mineral acid to give a pH within the range of 1.2 to 2.5, andsubjecting the acidified solution at a temperature of 20 C. to 50 C. toenzyme modification with the enzyme pepsin added in an amount of 0.05%to 0.7% by weight, expressed as 1:10,000 strength, of the proteincontent of the solution for 18 to 24 hours, thereafter heating thesolution to a temperature sufficient to stop the enzyme action,adjusting the pH of the resultant slurry to between 3.0 and 5.5 andheating said slurry to a temperature between 40 C. and 100 C. toprecipitate heat coaguable protein, separating the solubles from theinsolubles and recovering the solids from the soluble portion of theproduct.

9. A process as claimed in claim 8 in which said extract liquor issubjected to an acid hydrolysis instead of an alkaline hydrolysis.

10. A pepsin modified hydrolyzed protein obtained in accordance with theprocess of claim 1.

11. A pepsin modified hydrolyzed soya protein obtained in accordancewith the process of claim 2 and fur ther characterized as having awhipping capacity such that one part by weight of said protein whippedwith 100 parts by weight of a mixture of 60 parts corn syrup and 40parts sucrose will give 60-64 ounces per gallon of whipped product.

12. A bakery product mix adapted to provide an aerated bakery product,said mix containing the protein product as claimed in claim 10 in anamount effective to enhance the aeration of said mix.

13. A cake mix comprising a protein product as claimed in claim 10 in anamount effective to enhance the aeration of said mix.

14. A chocolate chifion pie mix comprising a protein product as claimedin claim 10 in an amount effective to enhance the aeration of said mix.

15. A bakery product adapted to provide an aerated bakery product, saidbakery product comprising whole eggs and a protein product as claimed inclaim 10 in an amount eflective to enhance the aeration of said eggs.

16. A process of aerating whole eggs which comprises whipping whole eggswith a protein product as claimed in claim 10 in an amount eifective toenhance the aeration of said eggs.

References Cited UNITED STATES PATENTS 1,373,651 4/1921 Cullen 991142,381,407 8/ 1945 Levinson 2601 12 FOREIGN PATENTS 478,777 1951 Canada99-17 X 478,778 1951 Canada 9917 OTHER REFERENCES Food Engineering,April 1959, pp. 104-105.

RAYMOND N. JONES, Primary Examiner US. Cl. XJR.

UNITED s'minics PATENT 0mm: CERHFECATE 0F CCRRECTION Patent No.3,814,816 Dated June 4, 1974 Invent0r(s) Robert th r It is certifiedthat error appears in the above-identified patent and that said LettersPatent are hereby corrected as shown below:

Column 2, line 7; for "to" read --and--- Column 2, line 9; for"predicted" read --predicated- Column 4, line 4; for "n" read --in---Column 4, line 29; for "1: 10,000" read ---(l: 10,000) Column 5, line31; for "l. 6 twenty" read --l. 6. Twenty- Column 5, line 35 for"causitc" read ---caustic--- Column 6, line 44; for "flakes" read---flake--- Column 7 line 4; for "peroid" read ---period-- Signed andsealed this 8th day of October 1974,

(SEAL) Attest:

c o MARSHALL DANN McCOY M, GIBSON JR Commissioner of Patents AttestingOfficer ORM PO-lOSO (10-69) USCOMM DC eo376 P69 u.s. GOVERNMENT PRINTINGOFFICE: 1969 0-366-334.

